Power regulator

• US 6,181,116 B1
• Filed: 05/22/1998
• Issued: 01/30/2001
• Est. Priority Date: 05/22/1998
• Status: Expired due to Fees

• Current Assignee: Minebea Electronics Motor Company Limited (MinebeaMitsumi Inc.)
• Original Assignee: NMB USA Incorporated (MinebeaMitsumi Inc.)
• Inventors: Jansen, Arian M.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Patel, Rajnikant B.
• Application Number:
  US09/083,760
• Time in Patent Office: 984 Days
• Field of Search: 323/302, 323/301, 323/261, 323/251, 323/247, 363/45, 363/46, 363/47, 363/48, 363/16, 363/90, 363/91, 363/21
• US Class Current: 323/261
• CPC Class Codes: H02M 7/066 particular circuits having a special characteristic
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A power regulator is provided which employs a resonant circuit and permits regulation between a certain maximum value and zero. A series resonant circuit is adjusted to regulate power by adjusting the correspondence between the resonance frequency and the frequency of the voltage source such as an AC source delivering a sine wave or a square wave. Further, the output voltage is regulated to be lower than the voltage of the AC source when output current is zero. A capacitance is connected in parallel with the output of the power regulator to form a second resonant circuit with the inductance of the series resonant circuit. A method of power regulation is also contemplated.

Claims

1. A power regulator comprising:

an AC source having a voltage and a frequency;

an output having an output voltage;

a first resonant circuit comprising a first inductance and a first capacitance connected in series to said AC source, and having a first resonance frequency;

means for adjusting the correspondence between the frequency of said AC source and the first resonance frequency of said first resonant circuit in order to regulate power; and

means for regulating to an output voltage lower than the voltage of said AC source when there is substantially zero output current.

2. The power regulator according to claim 1, wherein said means for regulating comprises a second capacitance connected in parallel with said output to form a second resonant circuit with said first inductance.

3. The power regulator according to claim 1, wherein said means for adjusting the correspondence between the frequency of said AC source and the first resonance frequency comprises means for varying the first inductance.

4. The power regulator according to claim 1, wherein said means for adjusting the correspondence between the frequency of said AC source and the first resonance frequency comprises means for varying the capacitance.

5. The power regulator according to claim 1, wherein said means for adjusting the correspondence between the frequency of said AC source and the first resonance frequency comprises means for varying said frequency of said AC source.

6. The power regulator according to claim 1, wherein said means for regulating permits an output power of essentially zero.

7. The power regulator according to claim 1, further comprising an isolation transformer having a primary winding and at least one secondary winding;

said primary winding connected in series with said first resonant circuit and said second winding operatively connected to said output of said power regulator.

8. The power regulator according to claim 2, further comprising an isolation transformer having a primary winding and at least one secondary winding;

said primary winding connected in series with said first resonant circuit and said second winding operatively connected to said output of said power regulator.

9. The power regulator according to claim 7, further comprising rectifier means connected to said secondary winding of said transformer to provide a DC voltage at said output of said power regulator.

10. The power regulator according to claim 9, wherein said rectifier means includes a series inductor.

11. The power regulator according to claim 9, wherein said second capacitance is set equal to or above a minimum value.

12. The power regulator according to claim 2, wherein said second resonant circuit has a second resonance frequency and said second capacitance is set at a value which permits less than one full wave of said second resonance frequency when a momentary value of the input current is larger than the output current Iout.

13. The power regulator according to claim 9, further comprising means for slowing the transition of forward current output from said rectifier means.

14. The power regulator according to claim 13, wherein said means for slowing the transition of forward current from said rectifier means comprises a series inductor.

15. The power regulator according to claim 9, further comprising means for eliminating sharp transitions in voltage across said rectifier means.

16. The power regulator according to claim 15, wherein said means for eliminating sharp transitions in voltage across said rectifier means comprises a series inductor.

17. The power regulator according to claim 9, further comprising means for reducing recovery losses associated with said rectifier means.

18. The power regulator according to claim 17, wherein said means for reducing recovery losses comprises a series inductor.

19. The power regulator according to claim 8, wherein said second capacitance is connected across the primary winding of said transformer.

20. The power regulator according to claim 8, wherein said second capacitance is connected across said secondary winding of said transformer.

21. The power regulator according to claim 7, wherein said first resonant circuit includes the leakage inductance of said isolation transformer.

22. The power regulator according to claim 8, wherein the value of the second capacitance is set to compensate for winding capacitances of said transformer.

23. A power regulator according to claim 7, further comprising rectifier means and wherein the value of the second capacitance is set to compensate for capacitances associated with said rectifier means.

24. A power regulator according to claim 7, wherein said transformer comprises a multitude of identical windings connected in series.

25. A power regulator according to claim 24, wherein said identical windings are wound multifilar.

26. A power regulator comprising:

an AC source having a voltage and a frequency;

an output having an output voltage;

a first resonant circuit comprising a first inductance and a first capacitance connected in series to said AC source, and having a first resonance frequency;

means for adjusting the correspondence between the frequency of said AC source and the first resonance frequency of said first resonant circuit in order to regulate power; and

a second capacitance connected in parallel with said output to form a second resonant circuit with said first inductance.

27. A method of regulating power comprising:

regulating the output voltage of a power regulator to a value lower than the voltage of an AC source when there is substantially zero current at said output.

28. The method according to claim 27, wherein said power regulator comprises a first resonant circuit comprising a first inductance and a first capacitance and said step of regulating the output voltage lower than the voltage of the AC source when there is zero output current includes providing a second capacitance connected in parallel with said output to form a second resonant circuit with said first inductance.